An organic electroluminescence (referred to herein as organic EL) display device is arranged with a light-emitting element in each pixel and displays an image by individually controlling the light emission. A light-emitting element includes a structure in which a layer (referred to herein as ) including an organic EL material is sandwiched between a pair of electrodes regarded as an anode electrode and cathode electrode. The organic EL display device is arranged with one electrode as a pixel electrode in each pixel and the other electrode as a common electrode which extends over a plurality of pixels and is applied with a common voltage. The organic EL display device controls the light emitted by a pixel by applying the voltage of the pixel electrode to each pixel with respect to the voltage of the common electrode.
In particular, a flexible display device which uses a substrate comprised from a thin polyimide (PI) resin and the like is being actively developed. In the manufacture of a flexible display device, a substrate (TFT side substrate) formed with a tin film transistor circuit element and light-emitting element in sequence is prepared above a resin such as a PI film or the like formed above a support substrate such as a glass substrate and the like. A substrate with a color filter above a resin such as a PI film and the like (CF side substrate) formed above a separate support substrate is prepared. A flexible display device including a thin PI resin substrate is obtained by bonding these substrates together, peeling both support substrates and dicing into separate pieces.
Here, since a PI resin substrate is very thin with a thickness of 10˜20 μm, it is effective to supplementary bond a film which protects the PI resin substrate with the aim of preventing deformation in a manufacturing process.
However, when a PI resin substrate deforms particularly in a peeling process of a support substrate or after peeling process, it becomes difficult to bond a film for protecting the PI resin substrate in subsequent processes which is a cause of a drop in manufacturing yield.
A structure is disclosed in Japanese Laid Open Patent No. 2013-157228 for example in which a formation protective layer is bonded to a substrate via adhesive layer or adhesion layer in order to prevent warping or distortions of the substrate in an organic EL device.